This invention relates to desiccant containing cartridges for use in receiver dryer or accumulator assemblies of automotive air conditioning systems. More specifically, it relates to desiccant cartridge retention devices used to secure desiccant cartridges to the fluid flow tubes and the canisters of these assemblies.
Although various forms of dryer assemblies have been suggested in the prior art, the types used in automotive air conditioning systems generally include an elongated receiver dryer or accumulator canister having inlet and outlet ports communicating with the interior of the canister. The outlet port generally consists of a fluid flow tube used to return the air or fluid flowing from the entry end of the canister to the exit end. The tube usually is positioned centrally within the canister. A desiccant cartridge holding desiccant particles is adapted to receive the fluid flow tube. The cartridge is positioned in the interior of the canister allowing for air or fluid to move through the desiccant particles.
It is important that the desiccant cartridge conform to the dimensions of the fluid flow tube as well as the canister in order to form a secure fit within the canister and to form a proper seal between the cartridge sleeve and the fluid flow tube, and between the cartridge and the canister. This task is made difficult due to manufacturing variations which produce canisters and fluid flow tubes with differing dimensions and sizes. As such, one must stock desiccant containers with various dimensions such that they properly can be fitted within these canisters and mounted on the fluid flow tubes. One obvious drawback with having to maintain a stock of desiccant cartridges having various dimensions is that inventory costs can become very expensive.
If a properly sized desiccant cartridge is not used, the cartridge will be able to move freely up and down inside the canister which can allow desiccant particles to shift and escape from the cartridge possibly resulting in damage to the air conditioning system. Further, an improper seal can cause leakage within the receiver/dryer or accumulator assembly or into the environment. Internal leakage can create icing within the air conditioning system, and environmental leakage can create a loss in fluid pressure as well as create potential health and environmental risks. As a result, an improper fit and improper seal can reduce the effectiveness of the air conditioning system.
In order to keep a desiccant cartridge secure within a receiver dryer or accumulator assembly and form a proper seal, desiccant cartridges must employ a retention device. Two types of retention devices used with today""s desiccant containers involve the use of pal nuts or the use of springs. However, both pal nuts and springs increase the cost of manufacture of the assembly and add a secondary installation operation.
Accordingly, there is a need in the art to provide a universal size cartridge adapted to fit substantially all of the commercially available accumulator and receiver/dryer canisters and fluid flow tube assemblies.
There is also a need in the art to reduce mold and piece cost by providing one desiccant cartridge mold that will fit many different canister and tube sizes thereby eliminating other positional holding devices and reducing assembly costs.
Lastly, there is a need to allow customers to purchase just one size desiccant cartridge to fit a broad range of fluid flow tubes and canister sizes.
These drawbacks and others are overcome by means of the present invention embodied in a desiccant containing cartridge.
This desiccant cartridge includes a cup extending along an axis and having spaced inner and outer wall portions connected by a transverse portion to define a chamber having an opening and a cap for receipt in the chamber. The inner wall portion defines a sleeve having first and second openings and further comprises an outer surface and an inner engagement surface. The sleeve is adapted to receive and the inner engagement surface adapted to cooperate with a fluid flow tube such as a dryer tube so that the desiccant cartridge is secured to the fluid flow tube forming a proper seal therebetween. The outer wall portion of the cartridge further is adapted to cooperate with a receiver dryer or accumulator canister such that the desiccant cartridge may be secured thereto also forming a proper seal. A cap is secured to the cup to retain the desiccant inside the chamber. Both the cap and the transverse portion are perforated to allow air or fluid to reach the desiccant housed therein.
In one embodiment, the inner engagement surface of the inner wall portion of the cartridge has a midpoint intermediate the first and second openings, and the sleeve diameter tapers in a direction from the first opening toward the midpoint forming a narrowed opening at the midpoint such that the sleeve is adapted to receive and the midpoint is adapted to cooperate with a fluid flow tube whereby the desiccant cartridge is secured thereto by a snug compression fit between the reduced diameter section of the sleeve and the fluid flow tube forming a proper seal therebetween.
Another embodiment consists of the inner engagement surface comprising a continuous flange projecting radially inwardly intermediate the first and second openings, and a continuous flange projecting radially outwardly from the outer wall portion intermediate the cup opening and transverse portion. The inner engagement surface flange is adapted to cooperate with a fluid flow tube, and the outer wall portion flange is adapted to cooperate with a canister such that the desiccant cartridge is lockingly secured to the fluid flow tube and canister forming a proper seal therebetween.
Accordingly, it is one object of the invention to provide a universally sized desiccant cartridge adapted to receive a variety of fluid flow tubes such as a dryer tube and fit within a variety of receiver/dryer and accumulator canisters of varying dimensions such that the cartridge is secured thereto forming a proper seal therebetween.
It is another object of the invention to reduce mold and piece cost by allowing one desiccant cartridge mold to fit many different canister and tube sizes thereby eliminating other positional holding devices and reducing assembly costs.
The invention will be further described in conjunction with the appended drawings and following detailed description.